1. Field of the Invention
This invention relates generally to food tray cleaning apparatus, and more particularly to a portable food tray pre-wash and water recycling apparatus and method that pre-washes food trays prior to placement in a separate cleaning and sanitizing unit and significantly reduces water wasted in kitchen and scullery areas aboard marine vessels, and in industrial, commercial, and institutional cafeterias.
2. Background Art
The present invention is directed toward an apparatus and method that pre-washes reusable food trays of the type that have compartments or shallow recesses formed in which food is placed, such as those used aboard marine vessels, and in industrial, commercial, and institutional cafeterias, prior to their placement in a separate cleaning and sanitizing unit and recycles the water used in the pre-wash operation. The advantage of reusable compartmented food trays is that the purchasing, stocking, distributing, collecting and washing is reduced to a single item. The main disadvantage is the requirement for washing the trays after each meal, and the amount of water wasted in the cleaning operation.
Typically, in the tray cleaning operation, after dumping the food from the trays, and prior to placing them in a conventional tray washing machine for cleaning and sanitizing, the trays are subjecting to a “scraping stage” where the food refuse is manually scraped from the trays and they are manually sprayed with water by a hand-held water jet nozzle with a squeeze trigger to remove the remaining food debris. The trays are usually manually sprayed for approximately 10 seconds per tray, and approximately 50 oz. of water is utilized with a conventional water jet nozzle. After use, the sprayed water is considered wastewater or “graywater” and is not recycled or reused.
Based on daily feed charts used by cooks aboard a naval frigate, it is estimated that a crew of 200 men will use about 445 trays per day in port (docked), and about 650 trays per day underway (at sea). Thus, in the example of a crew of 200 men, the amount of water used (wasted) daily by the conventional manual spraying method would be about 173.8 gallons per day in port (docked), and about 253.9 gallons per day underway (at sea). The amount of water wasted in this simple operation is significantly greater aboard larger vessels with larger crews, such as an aircraft carrier with a crew of 6,000. The amount of water wasted in this simple operation aboard aircraft carrier with a crew of 6,000 would be about 5,214 gallons per day in port (docked), and about 7,617 gallons per day underway (at sea).
Graywater is defined as the combined effluent wastewaters or drainage from shipboard galleys, sculleries, dishwashers, laundries, showers, sinks, and washbasins. Many ships directly discharge graywater, without treatment, into navigable waters, including lakes and waters near the shoreline. Some ships are equipped with concentration, holding, and transfer tanks for the purpose of storing graywater until it can be pumped to a dockside sanitation system. Graywater discharges in the past have not been subjected to permitting or regulatory requirements; however, as a result of increasingly stringent water quality standards being imposed under state, national, and international regulations, wastewater offload and disposal costs in domestic and foreign ports and harbors continue to increase.
These same problems are also present in industrial, commercial, and institutional cafeterias, that utilize reusable food trays in feeding large numbers of people.
Thus, there remains a need for an effective and economical means to reduce wastewater effluent, particularly graywater discharges from marine vessels, and to significantly reduce water wasted in kitchen and scullery areas in industrial, commercial, and institutional facilities.
There are several patents that are directed toward tray washing apparatus of various constructions, most of which are large, complex, elongate conveyor type apparatus that include a washing compartment and a sterilizing compartment, and associated mechanisms for receiving and transporting the trays through the compartments.
O'Connor, U.S. Pat. No. 2,651,065 discloses a tray washing and sterilizing machine having a slot in a top end of a side wall for inserting a food tray, spray nozzles, and a pair of rotating brushes at an upper end that spray and scrape both sides of the tray, and a removable filter screen (47) beneath the brushes that slides in from one side to filter the water, a water reservoir beneath the filters, a heating unit to heat and disinfect the water, and a pump to pump the heated water to the spray nozzles and to another set of nozzles in an adjacent sterilizing compartment. The trays are fed through the slot and pre-washed and then sterilized in the adjacent sterilizing compartment.
Kleebauer, U.S. Pat. No. 3,178,745 discloses a movable machine for washing plastic shields of fluorescent lights, which has a slot in a top end of a side wall for inserting a flat plastic panel, spray nozzles, and a pair of rotating brushes at an upper end that spray and scrape both sides of the panel, and two water reservoirs beneath the brushes, and a pump to pump recycle the water to the spray nozzles.
Richard, U.S. Pat. No. 3,938,533 discloses an automatic scullery apparatus for automatically processing carrying trays having used culinary items and refuse thereon that collects and cleans reusable culinary items (e.g. knives, forks and spoons), separates and disposes of waste, and cleans the trays without need for operating personnel. In preferred embodiments, the apparatus automatically stacks the cleaned trays and sorts and collects the cleaned reusable culinary items by type so that the trays and the culinary items are readily available for reuse.
Kitterman et al, U.S. Pat. No. 3,939,854 discloses a tray washing system that includes conveyors which transport compartmented food service trays from a tray receiving mechanism to inverting and scraping mechanisms and through washing, rinsing and drying mechanisms to a stacking mechanism. The receiving mechanism restricts trays to insertion in a predetermined orientation in which the food receiving surfaces face upwardly, and the inverting mechanism inverts each tray so that the food receiving surface faces downwardly. As each tray is inverted, the scraping mechanism discharges substantially the entire contents of a cleaning fluid reservoir onto the food receiving surface of the tray, and thereby dislodges refuse and silverware that may be on the tray. The washing, rinsing and drying mechanism apply a water-detergent solution, rinse water, and drying air to the trays, respectively, and the stacking mechanism deposits the trays onto a mobile self-depressing tray receiver. The tray washing system further includes a silverware separating and soaking mechanism comprising a chute which receives cleaning fluid and refuse and silverware entrained therein, a dam which removes the heavier silverware from the cleaning fluid, and a door in the bottom of the chute for dropping the silverware into a soaking sink.
Pure, U.S. Pat. No. 4,281,675 discloses a washing apparatus for washing insulated trays that includes an endless conveyor below the elevation of first and second guide rails that guide the trays in an upright disposition as they are being washed. The conveyor includes generally V-shaped tray supports at spaced points therealong so that each tray is supported by two adjacent tray supports. Vertically disposed manifolds have spraying nozzles for spraying water generally horizontally at opposite major faces of the trays.
Kleber, U.S. Pat. No. 5,581,836 discloses a compact wall-mounted or countertop-supported washing and sanitizing unit for cleaning and drying food service trays as well as other articles after being serially loaded in an upright manner in guide tracks that lead through the unit so that the trays process one at a time through adjacent washing and drying stations of the unit. After being manually loaded, an operator by exerting a displacement force on a last loaded tray urges preceding trays through the unit by virtue of their edge-to-edge physical contact.
The present invention is distinguished over the prior art in general, and these patents in particular by a portable food tray pre-wash and water recycling apparatus and method that pre-washes reusable food trays prior to placement in a separate cleaning and sanitizing unit and significantly reduces water wasted in kitchen and scullery areas aboard marine vessels, and in industrial, commercial, and institutional cafeterias. The apparatus includes a portable cabinet having a slot in a top end for inserting a food tray, laterally opposed spray nozzles beneath the slot that spray both sides of the tray, laterally opposed rotating brushes beneath the nozzles that scrub the tray, a tray support and brush comb member that supports the tray in a vertical position and removes particles from the brushes, a series of removable incrementally smaller gauge filter members vertically spaced beneath the brushes that slide in from one side to filter the water, a water collection reservoir beneath the filters, a heating unit to heat and disinfect the collected filtered water, and a pump to recycle the heated water back to the spray nozzles.